Here's how this theme could manifest in a story:
* The character may be struggling to differentiate between their own thoughts and the actual world around them. This could be due to mental illness, grief, or a traumatic experience.
* The character could be interacting with a ghost, a spirit, or a hallucination, blurring the lines between the real and the imagined.
* The character might be living in a simulated reality or a dystopian society where the true nature of their world is hidden.
* The story could explore the idea of the power of suggestion and the way our perceptions can be manipulated.
To understand the theme better, it's important to know the context of your question. What specific story or situation are you referring to? This will help to determine the specific nuances of the theme.